TM-9-2350-311-10
HOWITZER, MEDIUM, SELF-PROPELLED, 155MM; M109A2, M109A3, M109A4 AND M109A5
TECHNICAL MANUAL; OPERATOR’S MANUAL
NOVEMBER 1994
TM-9-2350-311-10 - Page 248 of 775
TM 9-2350-311-10
2–11 OPERATION OF FIRE CONTROL EQUIPMENT UNDER NORMAL CONDITIONS
— CONTINUED
2–11.3 M15 Elevation Quadrant
a. Description of the M15 Elevation Quadrant
1 Correction knob (1) sets correction counter plus window (2) or minus window (3) when turned.
2 Correction counter plus window (2) or minus window (3) registers correction factor for individual weapon.
3 Elevation knob (4) sets elevation counter (5) when turned.
4 Elevation counter (5) shows mils of gun elevation.
5 Cross-level knob (6) centers cross-level (7) bubble when turned.
6 Cross-level (7) is used for leveling.
7 Elevation level (8) is used for leveling.
8 Toggle switch (9) turns on lamp when pushed up.
9 M15 elevation quadrant seat (10) is a bar permanently mounted on top of the housing for seating the
M1A1 gunner’s quadrant.
b. Operating Procedures
1
2
3
4
2-150
NOTE
•
M15 elevation quadrant is used along with M117/M117A2 panoramic telescope in laying
weapon. If desired, functions of M15 elevation quadrant can be done using M145/M145A1
telescope mount.
• The following steps must be done to ensure correct announced quadrant is set on M15
elevation quadrant and will be performed by assistant gunner.
Turn correction knob (1) on M15 elevation quadrant (11) to place correction factor for individual weapon
in either correction counter plus window (2) or minus window (3).
Turn elevation knob (4) to put quadrant value commanded by Fire Direction Center (FDC) in elevation
counter (5).
Elevate or depress weapon to center elevation level (8) bubble.
NOTE
Use M1A1 gunner’s quadrant on Ml 5 elevation quadrant for fine elevation adjustments. Bubble
must be centered in cross-level using cross-level knob each time weapon is elevated,
depressed, or traversed.
Turn cross-level knob (6) to center cross-level (7) bubble.
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